## Why
zsh prints tied scalar/array exports such as `PATH` and `path` with `-T`
metadata. The snapshot filter rejected that syntax, so commands available only
through the configured `PATH` could not be resolved from a restored snapshot.
## What changed
- Recognize writable tied exports and retain them in zsh shell snapshots.
- Skip readonly exports so restoring a snapshot does not make variables such as
`PATH` immutable.
## Testing
Added macOS coverage for restoring a tied `PATH`, handling entries with spaces,
deduplicating path entries, excluding readonly tied exports, and resolving a
command available only through the restored snapshot.
GitOrigin-RevId: 297cfae3368230c7f6fe5ef84f0a10b35a2c802c
2deed3fb9c